In case of draw adjudication (0.05) and win adjudication by eval (6.50), the objective is to shorten the game by assigning the outcome that is likely to happen should the game continue. The problem with this particular case is that it produced a result that was extremely unlikely to happen in absence of adjudication.

If we accept the above TFD definition as essentially correct, it follows that the GUI took the wrong decision.

In case of draw adjudication (0.05) and win adjudication by eval (6.50), the objective is to shorten the game by assigning the outcome that is likely to happen should the game continue. The problem with this particular case is that it produced a result that was extremely unlikely to happen in absence of adjudication.

If we accept the above TFD definition as essentially correct, it follows that the GUI took the wrong decision.

you said yourself: by assigning the outcome that is likely to happen should the game continue; should the game have continued, unlimited by any specific rules, most likely SF would have won the game; indeed, such endgames are very easy to win for modern top engines.

hgm wrote:Actually they did write in the rules explicitly that the 50-move rule does apply.

they also wrote that Cutechess adjudicates automatically tablebase positions. what is the main rule and what the secondary one?

They did not write such adjudication could assign arbitrary results to the game that have no relation to the adjudicated position. This is sort of implied by the word 'adjudication'. If you assign a win to the bare King in KQQQK you cannot defend that by saying: "the rules stated that 5-men positions would be adjudicated".

So what happened was not adjudication. It was malfunctioning of the GUI during an attempt at adjudication.

I guess a won position is simply won, and the end position is won. FIDE rules concerning 50-moves draw is definitely a remnant from the past, and should be changed, the sooner the better.

Irrelevant. TCEC is played by FIDE rules, stupid as they might be. I'd also preferred to see that the captured pieces could be dropped back into the game, another defect of the current FIDE rules. But alas, these are the rules they play by...

So, what should be done, is for a specific engine protocol to change the 50-moves rule to a larger number, at least 100, maybe referring only to specifically known tablebase positions. The 50-moves rule migth hold true for any other case(not to make the game too long), but, in the case of a known tablebase position, the rule might be changed to 100 moves.

For example, if pawnless endgame (where primarily those positions occur) and tablebase win, 50-moves rule=2*50-moves rule. Not difficult to do, is it?

What should be done is stick to the rules as they were agreed upon. Whether better rules could be designed, or how much better they would be, is not relevant.

Lyudmil Tsvetkov wrote:you said yourself: by assigning the outcome that is likely to happen should the game continue; should the game have continued, unlimited by any specific rules, most likely SF would have won the game; indeed, such endgames are very easy to win for modern top engines.

I'll agree with those who say TCEC rules were followed, and the GUI should adjudicate this position. But it is wrong to feed engines that rely on TB one set that says the position is a draw, and then adjudicate based on another set that says it is a win for one side.

Debate the merit of the 50 move rule as it pertains to computer chess all you want. It is quite irrelevant to the situation.

The solution is very easy: admit this situation wasn't forseen, admit it is wrong to use different metrics for adjudication than the ones used by the engines, and amend the result so that adjudication was based on the same set the engines were using.

Lyudmil Tsvetkov wrote:you said yourself: by assigning the outcome that is likely to happen should the game continue; should the game have continued, unlimited by any specific rules, most likely SF would have won the game; indeed, such endgames are very easy to win for modern top engines.

But that is true only if "unlimited by any specific rules" meant "unlimited by the 50-move rule". Since the 50-move rule is implemented and would have taken effect automatically and without exception, that game would have surely ended in a draw.

hgm wrote:You seem to miss the point. The position is not a win, but a draw. And both engines saw that correctly.

So the relevant question is: if the position is a draw, why declare a win?

I don't understand. The TB said the position is a win. And the TB saw that BEFORE the 50 moves ended.
End of story!

THIS is how things have been adjudicated until now.
No one cared what the engines say and no one cared what human common sense say.
And as Cato said very clearly, TCEC allows use of TB's.
End of story!

(It's not me, it's Cato and most other members both here and in TCEC... UNTIL now! The question is, are we going to change this right now? Right in the milddle of this superfinal? If so, who gives us permission?)